Lower UTIs More Likely to Resolve With Nitrofurantoin Than Fosfomycin

 Lower UTIs More Likely to Resolve With Nitrofurantoin Than Fosfomycin

Women with uncomplicated lower urinary tract infections (UTIs) experience greater clinical and microbiologic resolution with nitrofurantoin than fosfomycin, according to a new study published in the Journal of the American Medical Association.

The guideline-recommended antibiotics were compared in a randomized controlled trial of 513 patients (median age 44 years) from Switzerland, Poland, and Israel. Participants received either oral macrocrystalline nitrofurantoin (100 mg 3 times daily) for 5 days or a single 3 g dose of oral fosfomycin tromethamine.

At 28 days after treatment, 70% of nitrofurantoin recipients had complete resolution of symptoms compared with 58% of fosfomycin-treated patients, Stephan Harbarth, MD, of Geneva University Hospitals and Faculty of Medicine in Switzerland and colleagues reported. Moreover, 74% vs 63% of recipients, respectively, experienced microbiologic resolution, defined as eradication of the bacterial strain with no recurrence of bacteriuria (less than 103 colony-forming units per mL).
No serious adverse events occurred. The most common side effects, nausea and diarrhea, developed in 3% and 1% of the nitrofurantoin group and 2% and 1% of the fosfomycin group, respectively. Duration of symptoms (4 vs 3 days) and pyelonephritis (0.4% vs 2%) were not significantly different between the nitrofurantoin and fosfomycin groups, respectively.

Despite its efficacy, nitrofurantoin yielded a lower than expected overall response rate. The team attributed this finding to a high incidence of non-Escherichia coli infections in the cohort. Both Proteus spp and Klebsiella spp exhibit resistance to nitrofurantoin.

In an accompanying editorial, Rupak Datta, MD, PhD, and Manisha Juthani-Mehta, MD, observed: “Outstanding issues remain the optimal nitrofurantoin dosing regimen and whether current recommendations of 100 mg twice daily are equally effective as 100 mg 3 times daily. The role of fosfomycin also requires examination. Clinical and microbiologic responses with alternative fosfomycin prescribing practices, such as fosfomycin 3 g followed by 3 g every 3 days for a total of 3 days, 6 days, or 9 days, for multidrug-resistant uropathogens should be tested.”

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